I’m in awe of your fins. especially those curved rail fins.
Even if they were molded from plastic I’d be impressed with the highly unconventional shape and design, but to be made from wood too…
I’d love to give them a go. My Proboxes accepts fcs1 fins…My mailing address is…:0
With no CNC machine I take way too many hours to make just one wood and fiberglass fin, and generally stop working on it before it is truly finished, mostly cosmetics, as I want to know if it works before going farther, and when they do work I tend to forget to complete them and just use them instead, or start making cardboard templates of the next version. If my latest fin works as hoped, then any flat sided rail fin I have made previous, is back to only 50% finished.
What kind of wood, and do you think the fcs tabs are strong enough? I’ve only made one large fin out of KOA wood, and not glassed it, just used teak oil, But it broke during a top turn where a large piece of kelp also was. I think the tab broke allowed the fin to rock back and then with all the load on the back half of the fin it just let go. I have made smaller sidebites from both Bloodwood and purpleheart with fcs1 tabs, flat sides, and used only teak oil to finish, but they were lacking something, performance wise.
I rebuilt the Koa fin, but then glassed it, and that was for a singlefin box .I drifted away from larger center fin with smaller side bites back to larger rail fins with smaller center in that board, and that board has been mostly shelved since I finished its larger version a few years back.
I’ve never even considered making a turbucle fin out of wood. I’ve modified MrMik’s 3d printed broken Gwhale fins to fit Probox, FCS2 and Futures center boxes with pultruded carbon bars from finbase into finbody . Have not yet finished the futures version. I found with the 50/50 foil I did not like them as rail fins, most of the wave, but sometimes on a better bigger wave, the flow and speed felt wonderful, but othertimes felt way too dull and drifty and imprecise. Blaming the 50/50 foil could be wrong. I made them ~4.5 inches deep and perhaps they need to be deeper. I had briefly tried 50/50 foils as conventional rail fins before and gotten that same imprecise feeling though. So many variables…
I’ve kept the cut down to size turbucle fins as center fins, with my sharkier cedar rail fins that employ the super high aspect, thicker foil, and narrow tip. I think their low drag, happily stalled and forgiving nature, make them great in this location, as long as they are moved back on the tail and one takes steps to prevent their leash catching it on take off. MrMik made a more extreme version of the Gwhale fin, which I did not like in the Longboard, compared to the Gwhale, but I have turned it into a fairly deep center fin for my 6’11" hws, and just completed moving its tab way forward, to move the fin way back. Not yet tried it. I tried it before the second modification/tab movement, with sharky rail fins, 3/4 inches farther forward un center box and it was way too loose/pivoty.
The FCS2 0.5 GW turbucle fin was described as very fast very loose and very weird, by my one test pilot, riding a board he ‘hated’. I was thinking with all the load on the rear portion of the FCS2 box, it might break the fcs2 box, and he claimed to not care if that occurred to that hated board. But it lasted 3 sessions with instructions to try and break it turning. I’m eagerly awaiting more feedback from when he puts it in a board he actually likes, and tries it in good waves and gets used to the new feeling and perhaps pushes the boundaries.
Do your curved turbucled rail fins have 50/50 foil or lesser on the inside, like 80/20. I can’t tell by the picture, I only can see they are not flat inside.
I’ve not played with toe in angles, yet. but Me thinks the accepted toe in formulae are dialed in for flat sided rail fins, and other foils need something different, more or less toe in I know not, but I suspect less. Cant seemingly get anyone still active here, to talk fin design in depth, especially unconventional fin design, and most of the local surfers i run into surfing who experiment with different fins, are simply too local and too cool and dismissive to discuss this topic in any depth, and seem to be of an opposite mindset, experimenting with lower aspect ratio/ more rake/exaggerated tips.
Seems google Chrome is not allowing me to upload any more photos. I get the little clock for a quarter second after clicking upload, then it disappears and nothing happens.